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Depleting our Aquifers at our Own Peril

“Don’t it always seem to go,” advised a mischievous Joni Mitchell in the “Big Yellow Taxi,”

“That you don’t know what you’ve got
Till it’s gone.”

She may have been singing about museum-bound trees, spotted apples, and lost love at the time, but if she were to add a stanza today, she might make mention of another precious resource that we can no longer take for granted.

Water.

The most essential ingredient to life on earth often makes its way to us from the mountaintops, snaking its way down from the heights in tiny rivulets and nurturing plants, mosses and ferns along the way. As brooks become streams, streams gather into creeks, and creeks combine into rivers, the stuff of life finally settles into the vast reservoirs we’ve created to collect it all—a practice we began, though on a much smaller scale, tens of thousands of years ago.

But this process of leveraging the snowpack that for millennia has amassed year after year among the tall peaks of the Sierras, Rockies, Catskills, Alps, and Himalayas may prove unsustainable as the world’s temperatures climb higher in the decades ahead. Yes, the winter snowpack may persist for months at the world’s highest elevations. But as annual temperatures continue to climb and snow no longer collects below 8,000 and then 9,000 and then 10,000 feet, the total water volume of the snowpack will diminish, and our reservoirs will no longer fill with the water melting from those high snowpacks as deeply as they have in the past.

Building more dams and reservoirs (as some have suggested) won’t help. Our planet simply isn’t producing enough combined rain and snowfall to fill the reservoirs that we already have. And we’re currently adding more than 75 million thirsty people to the world’s population every year.

Of course, in addition to the man-made reservoirs built by public works projects around the world, the planet created its own massive water repositories in submerged aquifers. We’ve drilled into the earth to retrieve this water too, and these wells have brought water for drinking and irrigation to individual families and communities for centuries. But drought, the increasing expense of maintaining existing water supplies, and the pressing need for irrigation to support the exponential agricultural growth needed to sustain the ever-increasing population has prompted us to pump an escalating volume of water out of those subterranean aquifers.

In a 60 Minutes segment called “Depleting the Water” that Lesley Stahl brought to us two years ago, we learned how quickly we’re draining those natural aquifers. Working with a hydrologist with the U.S. Geologic Survey, Ms. Stahl learned that the levels of water in test wells monitored by the Survey “have dropped about 200 feet in the last few years.”

To get an idea of how much water that 200-foot drop represents, consider what happened at another aquifer, the High Plains (or Ogallala) Aquifer in the Midwest. It’s a huge water source—“one of the world’s largest aquifers,” according to Wikipedia)—that sits below eight midwestern states. Stretching from southeastern Wyoming and nearly the entire state of Nebraska in the north to the Texas Panhandle in the south, the aquifer covers almost 174,000 square miles. Up to 1,000 feet deep in some places and 400 in others, the Ogallala provides drinking water to nearly 1.9 million people and “yields about 30% of the ground water used for irrigation in the United States.”

At one time, a pump at one Kansas farm supported by the aquifer was delivering as much as 1,600 gallons of water a minute to the farm’s thirsty corn crop, as reported by Michael Wines in “Wells Dry, Fertile Plains Turn to Dust.” That’s close to 100,000 gallons an hour; nearly 1.2 million gallons of water over a 12-hour period; 8.4 million gallons a week. And more than 436 million gallons of water a year.

Just one farm.

The result? “Since the 1940s, pumping from the Ogallala has drawn the aquifer down more than 300 feet (90 m) in some areas.” And a little more than a third of that drop occurred in just a 7-year period between 2001 and 2008. Although many farmers have switched to crops that require less water and conservation measures have increased, some estimates indicate that the “remaining [water] volume could be depleted as soon as 2028.”

That’s just 12 years from now. And once depleted, “the aquifer will take over 6,000 years to replenish naturally through rainfall.”

Nor are the California and Midwestern examples isolated incidents. According to an article published in The Washington Post last year, “the world’s largest underground aquifers—a source of fresh water for hundreds of millions of people—are being depleted at alarming rates, according to new NASA satellite data that provides the most detailed picture yet of vital water reserves hidden under the Earth’s surface.” The satellites don’t indicate how much water remains in these aquifers, so some (or all) of them may last longer than the anticipated 12 years of the High Plains Aquifer.

But, at the rate we’re depleting the reserves in these aquifers around the world, what are the 8.4 billion people estimated to inhabit this planet by 2030 going to do for drinking water 20, 50, or 100 years from now?

See the following for more information on the topics, above:
Climate Change in Colorado
Depleting the Water
Feds warn of new threats to water supplies with climate change
The Ogallala Aquifer
New NASA Data Show How the World Is Running Out of Water
Population Growth
Sierra Snowpack Strong, But Not Strong Enough to End Drought
Wells Dry, Fertile Plains Turn to Dust
Why some reservoirs don’t fill as quickly